Filament-support.



J. W. HOWELL.

FILAMENT SUPPORT.

APPLICATION FILED 1330.17, 1900.

Patented Apr. 30, 1912.

p t R We 0 EH N AM WITNESSES Zz vcitizen of the United States, residing at is illustrated as applied to lamps having portation is much simplified.

ameter they are fragile and subject to- UNITED STATES PATENT OFFICE. I a JOHN w. HOWELL, or NEWARK, NEW :rnnsnxhsmoiron. T5 GnNERAI. ELnc'rnIo i COMPANY, A conPoRArIo-n or ron c.

FILAMENT-suPPoRr.

- Specification 0: Letters intent.

To all whom it may concern: I

Be it known that- I JOHN W. HOWELL, a

Newark, county of Essex, State of New Jersey, have invented certainnew and useful Improvements in Filament-supports of which the following is a specification. J

This invention relates to an improvement in means for supporting-filaments in incandescent lamps.

In the drawings accompanying and forming a part .of this specification my invention filaments of refractory metal. Tungsten filaments and other refractory metal filaments of the general class of which tungsten is typical, have a tendency to soften at the exceedingly high temperature of operation and are also subject .toa progressive change in length due possibly to some complex molecular change. My improved supporting means not only holds the filament in proper position when plasticor softened by heat, but it also permits'this, progressive change of the filament without subjecting it to undue strains. In addition to allthis my improved supporting means is inert with respect to the filament and does not in any way introduce any impurity .or volatile foreign material into the envelop of the lamp which' might prove detrimental tothe filament. One of the modifications shown in the accompanying drawing has the additional advantage of protecting the filament from lateral shocks or jars which mightotherwise fracture the filament. 3 When metal filaments are made of very small dibreakage during transportation. '1 find, however, that by the use of this shock ra-' sisting means the percentage of breakage 1s greatly reduced and the problem of trans- In the drawings, Figure 1 is a perspective view of a metal filamentlamp suitable for use on a constant potentiaPsource of com-.= mercial voltage Fig. 2 is a similar view of a constant current lamp havinga filament considerably stronger than that illustrated in Fig. 1 and supported according to a modification of my invention; Figs; 3, 4 and 5 are details. I

The lamp shown in Fig- 1 is provided with the usual leading-in wires 1 and2sup plying current to a filament made up of five 7 separate loops 3', 4, 5,6 and 7 connected in series by means of metal conductors 8 radiating from a glass hub 9 mounted above the PatentedApr.30, 1912. Application filed December 17,1906. Serial No. 348,127. I

stem of the lamp. The filament may be connected with these radiating wires by welding, or in any suitable manner. Each of these fivel'oops issupported at the top by a refractory metal helix or coiled spring 10 disposed at an angle to the plane of the filament in such a way that a'progressive contraction of the filament will place the coiled springundmr a stress transverse to the axis of the coil. As these springs are in contact with the-intensely hot filamentv the advantages of making them of highly refractory materialare apparent. I.find that. tantalum wireis well adapted for this purpose. It is not only refractory but is. also I elastic and resilient. Furthermore, it is relatively inert and does not combine even at high temperatures I tive metal tungsten. I v

' As a means for supporting the fixed .ends

withthe relatively-ac? of the tantalum sprmgsyI utilize metal I standards "11, of copper or other ductile metal, fused in a glass knob 12 carried on a stem, These copper standards 11 are each provided with a clip at the-upper end thereof, as shown in-detail in Figs. 3,4 and 5.

This clip may be madeby flattening out the endof the copper wire as shown in Fig. 3, and then drawing the flattened end through -a die to roll it up into a tube into which the glass. pedestal 13 supported by 'the lamp pliers. until it assumes .theform shown in Fig. 5,.and thereby grips firmly the'end of the tantalum spring, and holds that endof the spring rigidly against movement. Theopposite end ;of the spring carrying the I shown in'Fi-g. ,1, this movement through a tungsten loop is free to move up and down large .arc will not increase materially- .the I tension on the supported filament It should be noted that. each filament in "the lamp'iS shrink quite independently of the others and without in anyway influencing the tension on ,the other loops. J 1

If a mop of'the type shown in Rig. 1318' independently supported and is free to:

to the filament loops, thecoiled helical springs 10 take up the force of'the jar or shock to which the filaments Would otherwise be subjected, by direct compression of the sprin s, and thereby greatly reduce the dan er 0 fracturing the filament. i

T e constant current or series lamp shown I in Fig. 2 is provided with arelatively heavy tungsten filament 14 which, because of its size, is not liable to breakage during transportation. This filament is supported at the top by a loop 15 made by twisting a ductile tantalum wire on itself. This tantalum wire is. pinched in the top of amet al standard or pe estal lfi supported by the lamp stem 17. This modification presents all the advantages of an inert supporting means arranged and permittlng permanent contraction therevention quite suitable'for refractory metal filaments of the larger cross-sections.

"' What I claim as new and desire tosecure by Letters Patent of the United States, is,--

prising a metal, wire standard with afiatand a resilient member held in said tube.

In witness whereof, 'I have hereunto set my hand this fourteenth dayof December, 1906. l

' Witnesses: S. N, WHITEHE'AD,

J. HARRY ELKINS.

at right angles to the plane of the filament .ioHN w. HOWELL,

of, and illustrates an embodiment of my in- 25 A supporting means-for filaments 'comtened vend portion having the form of a tube V 

